#include <iostream>
using std::endl;
using std::cout;


int add(const int& n)
{
    int end = 0;
    for (int i = 0; i < n; i++)
    {
        end += i;
    }
    return end;
}

int main()
{
    int n = 100;
    int result = add(n);
    cout << result << endl;

    cout << "hello 1" << endl;
    cout << "hello 2" << endl;
    cout << "hello 3" << endl;
    cout << "hello 4" << endl;
    cout << "hello 5" << endl;
    
    return 0;
}
